An apparatus for dispensing pharmaceutical articles includes a housing assembly and an adjustment system. The housing assembly includes a first inlet wall and a second inlet wall that is moveable relative to the first inlet wall. The housing assembly defines a hopper chamber that houses pharmaceutical articles, and a dispensing channel fluidly connected to the hopper chamber. The dispensing channel has an inlet and an outlet and defines a flow path. The inlet is defined at least in part by the first and second inlet walls. The adjustment system is operable to adjust the position of the second inlet wall relative to the first inlet wall to adjust the size of the inlet to singulate the pharmaceutical articles passing through the inlet. The adjustment system includes an input mechanism and an operator feedback mechanism. The input mechanism is selectively operable by an operator to selectively move the second inlet wall relative to the first inlet wall. The operator feedback mechanism provides tactile and/or audible feedback to the operator responsive to operation of the input mechanism by the operator to indicate prescribed increments of movement of the second inlet wall relative to the first inlet wall.